For protecting data security and for a purpose of redundancy (Disaster Recovery), storage vendors establish a geographic redundancy center to implement remote backup of data, so that original data is not lost or damaged after a disaster (such as a fire or an earthquake) occurs, and a key service can resume running in an allowable time range, to minimize a loss brought by the disaster.
Currently, a main storage system is a two-center storage system. The two-center storage system implements redundancy by establishing two data centers. Both the two data centers can receive a service request from a host, and store service data in respective storage devices. Then, data synchronization is implemented by using a link between the data centers. However, once a fault occurs on the link, the data synchronization is interrupted. Therefore, a data center needs to be designated to bear a data service of the host, and after fault recovery of the link, data received before the fault recovery is backed up to another data center.
Generally, when a fault occurs on the link, the two data centers immediately and respectively send arbitration requests to a quorum server, and the quorum server determines, according to an arbitration request receiving sequence, the data center that is to bear the data service.